The burnt wood technique is widely used today by professionals in architecture and construction for example. Little by little, we are beginning to see this method of shou sugi ban becoming more and more popular among private individuals. Indeed, everyone can burn their wood in DIY projects. In this article, we present the traditional technique of burning wood as well as a more modern method used by private individuals: the technique of burning wood with a blowtorch. We will also explain to you how to obtain colourful and contrasting shou sougi ban.
The burnt wood technique consists of obtaining a black layer of carbon on the visible surface of the wood by burning. This method originated in Japan. It traditionally consists of creating a triangle using 3 planks to create a fireplace. Then the fire is lit at the bottom of this chimney and rises up, burning the wood evenly. Brushing and wiping steps follow. This traditional technique remains difficult to do for individuals without too much experience.
Today, many alternatives are emerging, particularly for the do-it-yourself burnt wood technique. The most common is to use a torch to burn your wood. This method, which we will present to you later, is often used to make your own decorative objects or furniture in burnt wood for indoors or outdoors. This technique allows you to better control the quantity you burn. It is however much longer, which is why it is often used for small creations such as small decorative objects.
When it comes to burning larger surfaces such as cladding, for example, the burning of wood is often carried out by professionals.
The technique of wood burnt with a torch is applied to adapted species. In the traditional Japanese technique, it is cedar but you can burn pine, larch or oak. The type of wood chosen determines the final appearance of the burnt wood. Not all species will give the same result, it is up to you to make different tests to see which species of wood for shou sugi ban is right for you. We advise you to avoid hard woods such as walnut or exotic woods such as teak, which are very dense and difficult to carbonise.
With the burnt wood technique, you do not need to sand the wood. Burning the surface of the wood will remove any roughness. It is therefore easy to give a new look to damaged wooden furniture.
Torches with propane torches provide maximum flame control. Carbon formation occurs when the flame temperature is between 250 (482 F) and 500°C (932 F), so you need equipment that can reach 500°C (932 F) to burn your wood properly. The technique of burning wood with a torch is preferably carried out out outdoors (on windless days) to avoid the risk of fire. Wear fireproof gloves during the process, and keep water or a fire extinguisher nearby.
The size of the flame produced by the torch determines the heat and intensity of the burning. The smaller the flame, the more intense the burning will be because the heart of the flame is closer to the surface of the wood. Conversely, the larger the flame, the less intense the burning will be. The appearance of the burnt wood depends on the intensity of the burn, the colour obtained varies from one burnt wood to another. We advise you to test different burning intensities, for example on old wood, before you start creating burnt wood creations.
When you are going to burn the wood with a torch, you need to move the torch slowly from one end of the wood to the other in the direction of the fibres in order to get a homogeneous rendering. The torch must be held at the same distance from the wood to get a perfect finish. If small cracks appear at any time, it means that the burning is too intense, so you must reduce the intensity of the combustion. Within your wood, you have two types of veins: the spring veins and the denser summer veins. Most people who burn wood do not burn it deeply but only on the surface. This means that only the spring veins are burnt, the summer veins, which are denser and take longer to burn, are not charred. The combustion process cannot therefore be carried out at the same speed on all parts of the wood. It is often done with the naked eye and the technique of shou sugi ban with a blowtorch to obtain a homogeneous result is acquired with experience.
It is important to burn your wood thoroughly (even the summer veins) especially if you want to create interesting contrasts (also called coloured shou sugi ban) between the spring and summer veins.
Once the shou sugi ban technique has been carried out, you need to leave the wood to cool for about five to ten minutes. Then you have two options: either you brush the burnt wood to create effects and contrasts, or you leave the raw burnt wood as it is
If you want to create interesting contrasts, you can brush the wood. When the wood is burned thoroughly (3 to 5 millimetre layer), the spring and summer veins of the wood are burned. The brushing stage consists of removing the carbonised residues to obtain the colour you want. To do this, you need to brush the wood in the direction of the wood fibres with a standard wire brush. When you brush the wood, the spring veins, which are less dense than the summer ones, will eventually have less carbon. They will therefore be lighter than the summer veins because the carbon will be consumed more quickly when brushing. After brushing the wood, there is often some dust and soot left behind, it is important to remove these and apply finishing products afterwards. Use a damp cloth to remove the last residues present on the wood. For large surfaces, you can use an air compressor to release air on the surface of the brushed burnt wood and thus remove the remaining dust.
If you like the look of raw burnt wood, you can leave it as it is. The raw carbon layer is then extremely fragile. It is important to protect it to prevent it from crumbling. We advise you to use the Burnt Wood Protector PB600 which allows you to "fix" the carbon layer and prevent it from crumbling.
Burnt wood has various advantages. The technique of burning wood with a torch is often used to make interior or exterior decorations in burnt wood. If you use burnt wood for interior design, then it is mainly the aesthetic aspect that will interest you. For outdoor creations in burnt wood, the following advantages should be taken into account.
Moisture resistance: the carbonisation of the wood creates a 3 millimetre thick layer that makes the wood impermeable. Burnt wood does not warp or swell in contact with water and humidity. This property is very interesting if you want to create outdoor creations in burnt wood, for example around swimming pools.
Resistance to wood-boring insects: burnt wood loses cellulose (a nutrient for wood-boring insects). The wood becomes inhospitable to wood-boring insects, so you will not need to apply insecticide treatments to your burnt wood.
Fire resistance: the carbon layer is hard and becomes more difficult to burn.
Whatever technique you use to burn your wood, it is important to burn the wood thoroughly (3-5 millimetres thick), otherwise you will lose these technical advantages that naturally protect your burnt wood.
Finally, opting for the burnt wood method makes it possible to reuse old wood, scrap wood, and to give new life to sometimes unused wood. The burnt wood technique makes it possible to use woods that are not noble and to give them a new lease of life. In addition to an interesting aspect for DIY, burnt wood is an economical and ecological alternative.